Display apparatus using LCD panel

ABSTRACT

A projection apparatus ( 10 ) has an illumination section ( 68 ) that provides at least a first, a second, and a third component wavelength illumination. At least two component wavelength modulating sections accept and modulate the component wavelength illumination to provide a modulated component wavelength beam. Each component wavelength modulating section has a portion of a monochrome transmissive liquid crystal modulator panel ( 118 ) that has been segmented into at least a first, a second, and a third spatially separate portion. A component wavelength polarizer directs substantially polarized light to the corresponding portion of the monochrome transmissive liquid crystal modulator panel. An illumination path Fresnel lens focuses incident illumination from the component wavelength polarizer through the corresponding portion of the monochrome transmissive liquid crystal modulator panel. An analyzer conditions the polarization of the modulated component wavelength beam. A lens forms an image of superimposed component wavelength beams for projection onto a display surface ( 40 ).

FIELD OF THE INVENTION

This invention generally relates to electronic projection and moreparticularly relates to an electronic projection apparatus using asingle LC modulator panel for forming a full color projection image.

BACKGROUND OF THE INVENTION

Liquid crystal (LC) technology has been successfully harnessed to servenumerous display applications, ranging from monochrome alphanumericdisplay panels, to laptop computers, and even to large-scale full colordisplays. As is well known, an LC device forms an image as an array ofpixels by selectively modulating the polarization state of incidentlight for each corresponding pixel. Continuing improvements of LCtechnology have yielded the benefits of lower cost, improved yields andreliability, and reduced power consumption and with steadily improvedimaging characteristics, such as resolution, speed, and color.

One type of LC display component, commonly used for laptops and largerdisplay devices, is the so-called “direct view” LCD panel, in which alayer of liquid crystal is sandwiched between two sheets of glass orother transparent material. Continuing improvement in thin-filmtransistor (TFT) technology has proved beneficial for direct view LCDpanels, allowing increasingly denser packing of transistors into an areaof a single glass pane. In addition, new LC materials that enablethinner layers and faster response time have been developed. This, inturn, has helped to provide direct view LCD panels having improvedresolution and increased speed. Thus, larger, faster LCD panels havingimproved resolution and color are being designed and utilizedsuccessfully for full motion imaging.

Alternatively, miniaturization and the utilization of microlithographictechnologies have enabled development of LC devices of a different type.Liquid crystal on silicon (LCOS) technology has enabled the developmentof highly dense spatial light modulators by sealing the liquid crystalmaterial against the structured backplane of a silicon circuit.Essentially, LCOS fabrication combines LC design techniques withcomplementary metal-oxide semiconductor (CMOS) manufacturing processes.

Using LCOS technology, LC chips having imaging areas typically smallerthan one square inch are capable of forming images having severalmillion pixels. The relatively mature level of silicon etchingtechnology has proved to be advantageous for the rapid development ofLCOS devices exhibiting high speeds and excellent resolution. LCOSdevices have been used as spatial light modulators in applications suchas rear-projection television and business projection apparatus.

With the advent of digital cinema and related electronic imagingopportunities, considerable attention has been directed to developmentof electronic projection apparatus. In order to provide a competitivealternative to conventional cinematic-quality film projectors, digitalprojection apparatus must meet high standards of performance, providinghigh resolution, wide color gamut, high brightness, and frame-sequentialcontrast ratios exceeding 1,000:1. LCOS LCDs appear to have advantagesas spatial light modulators for high-quality digital cinema projectionsystems. These advantages include relatively large device size, smallgaps between pixels, and favorable device yields.

Referring to FIG. 1, there is shown a simplified block diagram of aconventional electronic projection apparatus 10 using LCOS LCD devices.Each color path (r=red, g=green, b=blue) uses similar components forforming a modulated light beam. Individual components within each pathare labeled with an appended r, g, or b, appropriately. Following thered color path, a red light source 20 r provides unmodulated light,which is conditioned by uniformizing optics 22 r to provide a uniformillumination. A polarizing beamsplitter 24 r directs light having theappropriate polarization state to a spatial light modulator 30 r whichselectively modulates the polarization state of the incident red lightover an array of pixel sites. The action of spatial light modulator 30 rforms the red component of a full color image. The modulated light fromthis image, transmitted along an optical axis O_(r) through polarizingbeamsplitter 24 r, is directed to a dichroic combiner 26, typically anX-cube or a Philips prism. Dichroic combiner 26 combines the red, green,and blue modulated images from separate optical axes O_(r)/O_(g)/O_(b)to form a combined, multicolor image for a projection lens 32 along acommon optical axis O for projection onto a display surface 40, such asa projection screen. Optical paths for blue and green light modulationare similar. Green light from green light source 20 g, conditioned byuniformizing optics 22 g is directed through a polarizing beamsplitter24 g to a spatial light modulator 30 g. The modulated light from thisimage, transmitted along an optical axis O_(g), is directed to dichroiccombiner 26. Similarly red light from red light source 20 r, conditionedby uniformizing optics 22 r is directed through a polarizingbeamsplitter 24 r to a spatial light modulator 30 r. The modulated lightfrom this image, transmitted along an optical axis O_(r), is directed todichroic combiner 26.

Among examples of electronic projection apparatus that utilize LCOS LCDspatial light modulators with an arrangement similar to that of FIG. 1are those disclosed in U.S. Pat. No. 5,808,795 (Shimomura et al.); U.S.Pat. No. 5,798,819 (Hattori et al.); U.S. Pat. No. 5,918,961 (Ueda);U.S. Pat. No. 6,010,221 (Maki et al.); U.S. Pat. No. 6,062,694 (Oikawaet al.); U.S. Pat. No. 6,113,239 (Sampsell et al.); and U.S. Pat. No.6,231,192 (Konno et al.)

As each of the above-cited patents shows, developers of motion-picturequality projection apparatus have primarily directed their attention andenergies to LCOS LCD technology, rather than to solutions usingTFT-based, direct view LC panels. There are a number of clearly obviousreasons for this. For example, the requirement for making projectionapparatus as compact as possible argues for the deployment ofminiaturized components, including miniaturized spatial lightmodulators, such as the LCOS LCDs or other types of compact devices suchas digital micromirrors. The highly compact pixel arrangement, withpixels typically sized in the 10–20 micron range, allows a single LCOSLCD to provide sufficient resolution for a large projection screen,requiring an image in the range of 2048×1024 or 4096×2048 pixels orbetter as required by Society of Motion Picture and Television Engineers(SMPTE) specifications for digital cinema projection. Other reasons forinterest in LCOS LCDs over their direct-view LCD panel counterpartsrelates to performance attributes of currently available LCOScomponents, attributes such as response speed, color, and contrast.

Yet another factor that tends to bias projector development effortstoward miniaturized devices relates to the dimensional characteristicsof the film that is to be replaced. That is, the image-forming area ofthe LCOS LCD spatial light modulator, or its digital micromirror device(DMD) counterpart, is comparable in size to the area of the image framethat is projected from the motion picture print film. This may somewhatsimplify some of the projection optics design. However, this interest inLCOS LCD or DMD devices also results from an unquestioned assumption onthe part of designers that image formation at smaller dimensions is mostfavorable. Thus, for conscious reasons, and in line with conventionalreasoning and expectations, developers have assumed that theminiaturized LCOS LCD or DMD provides the most viable image-formingcomponent for high-quality digital cinema projection.

One problem inherent with the use of miniaturized LCOS and DMD spatiallight modulators relates to brightness and efficiency. As is well knownto those skilled in the imaging arts, any optical system is constrainedby the LaGrange invariant. A product of the area of the light-emittingdevice and the numerical aperture of the emitted light, the LaGrangeinvariant is an important consideration for matching the output of oneoptical system with the input of another and determines outputbrightness of an optical system. In simple terms, only so much light canbe provided from an area of a certain size. As the LaGrange invariantshows, when the emissive area is small, a large angle of emitted lightis needed in order to achieve a certain level of brightness. Addedcomplexity and cost result from the requirement to handle illuminationat larger angles. This problem is noted and addressed in commonlyassigned U.S. Pat. Nos. 6,758,565 (Cobb et al.); U.S. Pat. No. 6,808,269(Cobb); and U.S. Pat. No. 6,676,260 (Cobb et al.) These patents discloseelectronic projection apparatus design using higher numerical aperturesat the spatial light modulator for obtaining the necessary light whilereducing angular requirements elsewhere in the system.

A related consideration is that image-forming components also havelimitations on energy density. With miniaturized spatial lightmodulators, and with LCOS LCDs in particular, only so much energydensity can be tolerated at the component level. That is, a level ofbrightness beyond a certain threshold level can damage the deviceitself. Typically, energy density above about 15 W/cm² would beexcessive for an LCOS LCD. This, in turn, constrains the availablebrightness when using an LCOS LCD of 1.3 inch in diameter to no morethan about 15,000 lumens. Heat build-up must also be prevented, sincethis would cause distortion of the image, color aberrations, and couldshorten the lifespan of the light modulator and its support components.In particular, the behavior of the absorptive polarization componentsused can be significantly compromised by heat build-up. This requiressubstantial cooling mechanisms for the spatial light modulator itselfand careful engineering considerations for supporting opticalcomponents. Again, this adds cost and complexity to optical systemdesign.

Still other related problems with LCOS LCDs relate to the high angles ofmodulated light needed. The mechanism for image formation in LCD devicesand the inherent birefringence of the LCD itself limit the contrast andcolor quality available from these devices when incident illumination ishighly angular. In order to provide suitable levels of contrast, one ormore compensator devices must be used in an LCOS system. This, however,further increases the complexity and cost of the projection system. Anexample of this is disclosed in commonly-assigned U.S. Pat. No.6,831,722 (Ishikawa et al.), which discloses the use of compensators forangular polarization effects of wire grid polarizers and LCD devices.For these reasons, it can be appreciated that LCOS LCD and DMD solutionsface inherent limitations related to component size and light pathgeometry.

There have been various projection apparatus solutions proposed usingthe alternative direct view TFT LC panels. However, in a number ofcases, these apparatus have been proposed for specialized applications,and are not intended for use in high-end digital cinema applications.For example, U.S. Pat. No. 5,889,614 (Cobben et al.) discloses the useof a TFT LC panel device as an image source for an overhead projectionapparatus. U.S. Pat. No. 6,637,888 (Haven) discloses a rear screen TVdisplay using a single subdivided TFT LC panel with red, green, and bluecolor sources, using separate projection optics for each color path.Commonly-assigned U.S. Pat. No. 6,505,940 (Gotham et al.) discloses alow-cost digital projector with a large-panel LC device encased in akiosk arrangement to reduce vertical space requirements. While each ofthese examples employs a larger LC panel for image modulation, none ofthese designs is intended for motion picture projection at highresolution, having good brightness levels, color comparable to that ofconventional motion picture film, acceptable contrast, and a high levelof overall image quality.

One attempt to provide a projection apparatus using TFT LC panels isdisclosed in U.S. Pat. No. 5,758,940 (Ogino et al.) In the Ogino et al.'940 apparatus, one or more Fresnel lenses is used to provide collimatedillumination to the LC panel; another Fresnel lens then acts as acondenser to provide light to projection optics. Because it provides animaging beam over a wide area, the Ogino et al. '940 apparatus isadvantaged for its high light output, based on the Lagrange invariantdescribed above. However, while it offers potential applications for TVprojection apparatus and small-scale projectors, the proposed solutionof the Ogino et al. '940 disclosure falls short of the performancelevels necessary for high-resolution projection systems that modulatelight and provide imaged light output having high intensity, at levelsof 10,000 lumens and beyond.

Thus, it can be seen that, although digital cinema projection apparatussolutions have focused on the use of LCOS LCDs for image forming, thereare inherent limitations in brightness and efficiency when using LCOSLCD components for this purpose. TFT LC panel solutions, meanwhile,would provide enhanced brightness levels over LCOS solutions. Whileprojection apparatus using TFT LC panels have been disclosed, these havenot been well suited to the demanding brightness requirements ofhigh-performance digital cinema projection.

In cinema applications, the projector projects the modulated image ontoa display screen or surface, where this surface may be at a variabledistance from the projector. This requires that the projector providesome type of focus adjustment as well as color alignment adjustment.With conventional LCOS apparatus such as that shown in FIG. 1, coloralignment is performed by color combining optics, so that the threecomposite RGB colors are projected along the same axis. However, forsolutions using TFT devices, there would be benefits to providingseparate projection optics for red, green, and blue paths. Some of thesebenefits include simpler and less costly lenses with color correctionfor a narrow wavelength band at each lens. With such an approach, somealignment method must then be provided to form the color image fromproperly superimposed red, green, and blue images, thereby allowing theprojector to be used over a range of distances from a display screen.

Other problems relate to the nature of light modulation by the TFT LCdevice and to the support components necessary for high brightnessapplications requiring high levels of image quality. Conventionalsolutions would constrain both the light output levels and overall imagequality, obviating the advantages afforded by TFT use for projectionapplications. For example, the use of absorptive polarizers directlyattached to the TFT panels, as these devices are commonly provided, isdisadvantageous for image quality. Heat absorption from these films,typically exceeding 20% of the light energy, causes consequent heatingof the LCD materials, resulting in a loss of contrast and contrastuniformity.

Thus, it can be seen that there is a need for a full-color projectionapparatus that takes advantage of inherent etendue-related advantages ofTFT LC devices and provides improved image quality.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a projectionapparatus comprising:

-   -   a) an illumination section comprising:        -   i) a light source providing a substantially unpolarized            illumination beam of multiple wavelengths;        -   ii) a multiple wavelength polarizer for polarizing the            substantially unpolarized illumination beam to provide a            substantially polarized illumination beam of multiple            wavelengths;        -   iii) a uniformizer for conditioning the substantially            polarized illumination beam of multiple wavelengths to            provide a uniformized polarized beam of multiple            wavelengths;        -   iv) a color separator for separating the uniformized            polarized beam of multiple wavelengths into at least a first            component wavelength illumination, a second component            wavelength illumination, and a third component wavelength            illumination;    -   b) at least two component wavelength modulating sections, each        component wavelength modulating section accepting a        corresponding component wavelength illumination and modulating        the component wavelength illumination to provide a modulated        component wavelength beam, each component wavelength modulating        section comprising:        -   i) a portion of a monochrome transmissive liquid crystal            modulator panel that has been segmented into at least a            first portion, a second portion, and a third portion,            wherein each portion is spatially separated from each other            portion;        -   ii) a component wavelength polarizer in the path of the            component wavelength illumination for directing            substantially polarized light to the corresponding portion            of the monochrome transmissive liquid crystal modulator            panel;        -   iii) an illumination path Fresnel lens for focusing incident            illumination from the component wavelength polarizer through            the corresponding portion of the monochrome transmissive            liquid crystal modulator panel;        -   iv) an analyzer for conditioning the polarization of the            modulated component wavelength beam;        -   v) a lens for forming an image for projection onto a display            surface; and    -   whereby the image formed on the display surface comprises a        plurality of superimposed component wavelength beams.

It is a feature of the present invention that, unlike current approachesthat use miniaturized LCOS LCDs, the apparatus of the present inventionemploys a single LCD panel for imaging in a projection apparatusintended for high-end electronic imaging applications.

It is an advantage of the present invention that it allows addedbrightness for the projected image. Various types of light sources couldbe used.

These and other objects, features, and advantages of the presentinvention will become apparent to those skilled in the art upon areading of the following detailed description when taken in conjunctionwith the drawings wherein there is shown and described an illustrativeembodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims particularly pointing outand distinctly claiming the subject matter of the present invention, itis believed that the invention will be better understood from thefollowing description when taken in conjunction with the accompanyingdrawings, wherein:

FIG. 1 is a block diagram showing a conventional projection apparatususing LCOS LCD devices;

FIG. 2 is a block diagram showing a projection apparatus using alarge-scale TFT LC display according to the present invention;

FIG. 3 is a plan view of a TFT LC device segmented according to thepresent invention;

FIG. 4 is a perspective view of a projection apparatus according to thepresent invention;

FIG. 5 is a block diagram showing a projection apparatus with a controlloop for alignment;

FIG. 6 is a plan view of an LCD modulator panel subdivided intocomponent color modulating sections according to the present invention;

FIG. 7 is a schematic block diagram of a control loop for automatedalignment of projection lenses in one embodiment;

FIG. 8 is a schematic block diagram showing a projection apparatus in analternate embodiment;

FIG. 9A is a cross section of a conventional large panel LC device;

FIG. 9B is a cross section of a simplified large panel LC deviceaccording to the present invention;

FIG. 10 is a schematic block diagram showing an alternate embodimentwith two Fresnel lenses in each color channel;

FIG. 11 is a schematic block diagram showing an alternate embodimentusing color scrolling in a two panel apparatus;

FIG. 12 is a schematic block diagram showing an alternate embodiment inwhich an intermediate image is formed for projection;

FIG. 13 is a schematic diagram, in perspective, showing an alternateembodiment using a polarization beamsplitter in each color channel;

FIG. 14 is a schematic block diagram showing an alternate embodiment ofa portion of a color projection apparatus using a V-prism as colorcombiner for modulated light;

FIG. 15 is a schematic block diagram showing an embodiment using a colorwheel as color scrolling device; and

FIG. 16 is a schematic block diagram showing the use of a polarizationbeamsplitter as an analyzer in one color channel.

DETAILED DESCRIPTION OF THE INVENTION

The present description is directed in particular to elements formingpart of, or cooperating more directly with, apparatus in accordance withthe invention. It is to be understood that elements not specificallyshown or described may take various forms well known to those skilled inthe art.

Referring to FIG. 2, there is shown an embodiment of a projectionapparatus 50 designed for large-scale, high-brightness projectionapplications according to an embodiment of the present invention. Unlikeconventional projection apparatus described in the background sectiongiven above, projection apparatus 50 utilizes techniques to boostoverall efficiency and light output, suited to the demandingrequirements of high luminance projection. FIG. 4 shows key componentsof projection apparatus 50 in a perspective view. FIG. 4 isrepresentative for a configuration in which LC modulator panel 60 issegmented into three portions in side-by-side or horizontal fashion;this is an alternative to the configuration of FIG. 2 in which modulatorpanel 60 is segmented vertically. The best configuration for anyparticular embodiment, whether segmented vertically or horizontally, asdescribed subsequently, would depend on the overall width:height aspectratio of LC modulator panel 60 and the intended image 64.

An illumination section 68 has a light source 20 for providingunpolarized illumination having multiple wavelengths, typically, whitelight. Light source 20 directs this illumination to a multiplewavelength polarizer 74 for providing a substantially polarizedillumination beam 66. A lens 34 directs polarized illumination beam 66to a uniformizing element 22 to provide a uniformized polarized beam 76having multiple wavelengths. A condensing lens 38 then directsuniformized polarized beam 76 to a color separator 78 that separates themultiple wavelengths into component color wavelengths, conventionallyred, green, and blue (RGB) along separate illumination paths 44 r (red),44 g (green) and 44 b (blue).

There are at least three component wavelength modulating sections 114 r,114 g, 114 b, as shown in FIG. 2, each aligned along a correspondingillumination path 44 r, 44 g, 44 b. In each component wavelengthmodulating section 114 r, 114 g, 114 b, a condensing lens 42 r, 42 g, 42b directs the corresponding component wavelength illumination through apolarizer 48 r, 48 g, 48 b. Fresnel lenses 52 r, 52 g, and 52 b thenfocus this illumination through a monochrome transmissive liquid crystalmodulator panel 60 that is segmented to handle each component color formodulation, as is described subsequently. Liquid crystal modulator panel60 forms red, green, and blue component wavelength beams 54 r, 54 g, and54 b. Component wavelength beams 54 r, 54 g, and 54 b are the modulatedlight beams that are combined to form the color image. Analyzers 56 r,56 g, and 56 b condition the polarization of red, green, and bluecomponent wavelength beams 54 r, 54 g, and 54 b prior to projection byprojection lenses 62 r, 62 g, and 62 b that project each of themodulated component wavelength beams 54 r, 54 g, and 54 b respectivelyto a display surface 70. Here, the modulated component wavelength beams54 r, 54 g, and 54 b are superimposed to form a color image 64 ondisplay surface 70.

Broadband Polarization

Referring to FIG. 5, exemplary components of multiple wavelengthpolarizer 74 in a polarized light providing apparatus 110 withinillumination section 68 are shown in more detail. In this embodiment, apolarizer 96 transmits light having p-polarization and reflects lighthaving s-polarization. A mirror 98, or reflective polarization sensitivecoating, then directs the light having s-polarization through a halfwave plate 94. Half wave plate 94 converts this incident light top-polarization. In this way, polarized illumination beam 66 at lens 34has the same polarization state. Thus, substantially all of the lightoutput from light source 20 is converted to light having the samepolarization state for modulation. This method provides light over awider area and can be used with larger transmissive LC panels.Conventional LCOS LCD projection systems, limited by the LaGrangeinvariant, cannot fully take advantage of this type of light output.

In one embodiment, polarizer 96 is a wire grid polarizer, such as thepolarizer type disclosed in U.S. Pat. No. 6,452,724 (Hansen et al.) Wiregrid polarizers of various types are commercially available from Moxtek,Inc., Orem, Utah. The wire grid type of polarizer is particularlyadvantaged for handling high levels of light intensity, unlikeconventional types of absorptive polarizer. In one embodiment this wiregrid polarizer would be placed such that its wire elements on its wiresurface side face toward the LCD panel. This configuration reducesthermally induced birefringence as disclosed in commonly assigned U.S.Pat. No. 6,585,378 (Kurtz et al.) Polarizer 96 could alternately be aconventional prism polarizer, such as a MacNeille polarizer, familiar tothose skilled in the electronic imaging arts.

Illumination Source and Optics

A notable improvement over conventional TFT LC projection apparatus isthe use of uniformizing optics 22 for providing a uniform illuminationfrom a light source 20. Uniformizing optics 22 condition the output fromlight source 20 to provide a uniformly bright illumination beam formodulation. In one embodiment, an integrating bar provides uniformizingoptics 22. Alternate embodiments include the use of a lenslet array orsome combination of lenslet and other integrating components.

Light source 20 can be any of a number of types of lamp or otheremissive component. It can be appreciated that it would be particularlyadvantageous to select a commercially available component as lightsource 20, to take advantage of low cost and availability due to highmanufacturing volumes. In one embodiment, a conventional CERMAX® xenonarc lamp, available from PerkinElmer Inc., Wellesley, Mass., is used.The capability to use such off-the-shelf devices is a particularadvantage when using a larger size TFT LC device, as opposed to usingsmaller LCOS components that typically require custom light sourcesolutions. Other alternative light sources include high-power LEDs,which can be distributed in an array when using uniformizing optics 22.Another option is to use ultra-high pressure Mercury lamps, for example.Conventional xenon bubble lamps offer yet another option and providebetter color gamut than Mercury lamps.

An optional shutter 116, whose position may be at the location of thedotted line in FIG. 2, may be implemented within illumination system 68in order to momentarily darken the display to allow time for a suitabletransition between images. Shutter 116 may be needed depending on LCmodulator panel 60 response speed. Although response speeds of LCmodulator panels 60 have improved sufficiently for conventional video,it remains to be seen if there will be sufficient improvement to allowimaging with ghost free motion, particularly with image content thatcontains considerable action and transitions. Shutter 116 would be usedto block the light to LC modulator panel 60 during transition times,effectively reducing the overlay of images between frames. A suitableshutter mechanism is disclosed, for example, in commonly-assigned U.S.Pat. No. 6,513,932 (Ehrne et al.)

Color Separation

As was shown in FIG. 2, uniformized polarized beam 76 that is outputfrom uniformizing optics 22 next goes to color separator 78. FIG. 6shows the components of color separator 78 in more detail. Anarrangement of crossed dichroic surfaces 90 a, 90 b is used to split themultiple wavelength light of uniformized polarized beam 76 into the keyred, green, and blue component wavelengths for modulation as red, green,and blue component wavelength beams 54 r, 54 g, and 54 b, respectively.Turning mirrors 92 redirect red and blue component wavelength beams 54 rand 54 b in the embodiment of FIG. 6. Alternate embodiments include useof dichroic separating components in a fashion such that more than threecolor bands are separated, enabling a larger color gamut.

The improved light efficiency afforded by modulator panel 60 can beutilized to provide a projection gamut that is substantially larger thanthat provided using conventional video, such as SMPTE “C” color space oreven proposed Digital Cinema SMPTE gamut defined by (Red: 0.680 x, 0.320y, 10.1 Y, Green: 0.265 x, 0.690 y, 34.6 Y, Blue: 0.150 x, 0.060 y, 3.31Y). There is interest in making the gamut at least as large or largerthan that of motion picture film. Dichroic filters can be selected andpositioned to block portions of the spectral bands between the typicalcomponent color bands blue, green, and red, thereby increasing the colorspace that projection apparatus 10 works within.

Configuration of Modulator Panel 60

One aspect of the present invention relates to the segmentation ofmonochrome liquid crystal modulator panel 60, as shown in the plan viewof FIG. 6. The red, green, and blue component colors in respective red,green, and blue illumination paths 44 r, 44 g, and 44 b (FIG. 2) aremodulated by a red component modulating section 80 r; a green componentmodulating section 80 g, and a blue component modulating section 80 b,respectively. In one embodiment, where LC modulator panel 60 has2048×3240 pixel resolution, each component color modulating section 80r, 80 g, and 80 b has 2048×1080 pixel resolution. Higher resolutionpanel alternatives would be advantaged for applications such as digitalcinema.

Each modulating section 80 r, 80 g, 80 b has a corresponding borderportion 82 r, 82 g, 82 b. Border portions 82 r, 82 g, 82 b include somenumber of pixels that are unused but available to be used as part ofmodulating section 80 r, 80 g, 80 b. Border portions 82 r, 82 g, 82 bare used to facilitate alignment of the component color modulated light,as is described subsequently.

Each modulating section 80 r, 80 g, 80 b is separated from its adjacentmodulating section(s) 80 r, 80 g, 80 b by a light blocking segment 84 a,84 b. Light blocking segments 84 a, 84 b consist of pixels in a dark orblack state, acting as masks for reflecting overlapping light fromadjacent red, green, and blue illumination paths 44 r, 44 g, and 44 b.Physical blocking elements may be used in addition to or in lieu ofthese dark state pixels.

In the embodiments of FIGS. 2–4, LC modulator panel 60 is modified andsimplified for use in a projection application. Referring first to FIG.9A, there is shown a conventional LC modulator panel 118 as provided bythe manufacturer for display use. In this conventional arrangement, LCmaterial 120, with its control electrodes on an ITO layer 124 andthin-film transistors 122 is sandwiched between plates of glass 126,along with a color filter array 132. Front and rear polarizers 128 areabsorptive sheets whose performance is compromised by high heat levels,causing variable thermal nonuniformities in the projected image. Acompensation film 130 is also provided for enhancing contrast. In manydevices, other enhancement films are used but not shown, such asdiffusing layers.

FIG. 9B shows the simplified arrangement of LC modulator panel 60 asused in the present invention. Compensation film 130 may be removed;even if maintained, the performance requirements and cost ofcompensation film 130 are significantly reduced. Front and rearpolarizers 128 are also removed from LC modulator panel 60 itself;separate wire grid polarizers are used for polarizers 48 r, 48 g, 48 band analyzers 56 r, 56 g, 56 b. Polarizers 48 r, 48 g, 48 b andanalyzers 56 r, 56 g, 56 b are spaced apart from the surface of glasssheets 126. Wire grid polarizers, capable of handling high light levelswithout absorbing substantial amounts of light energy, are particularlywell suited to high intensity application in projection apparatus 50.Spacing them apart from LC material 120 prevents heat transfer thatwould negatively impact the uniformity of the image. Color filter array132 is no longer needed. An optional antireflection coating 134, 136 maybe provided on both external surfaces of glass 126. Antireflectioncoating 134, 136 would help to reduce checkerboard effects and increasethe ANSI contrast ratio, minimizing the interactions of neighboringpixels from stray light.

Fresnel Lenses

Use of Fresnel lenses 52 r, 52 g, and 52 b in illumination paths 44 r,44 g, and 44 b, as shown in FIG. 2, is particularly advantageous fordirecting light toward the entrance pupils of corresponding projectionlenses 62 r, 62 g, and 62 b. By placing Fresnel lenses 52 r, 52 g, and52 b in illumination paths 44 r, 44 g, and 44 b, imaging aberrations areminimized. Fresnel lenses are typically molded and may exhibitnonuniformities that are particularly visible if the lens is used withimage-modulated light.

FIG. 10 shows an alternate embodiment using a pair of Fresnel lenses ineach component wavelength modulating section 114 r, 114 g, and 114 b,one placed as an illumination path Fresnel lens in each illuminationpath 44 r, 44 g, 44 b, the other placed as a modulated beam Fresnel lensin each modulated component wavelength beam 54 r, 54 g, 54 b. In theblue color channel, Fresnel lens 52 b is in illumination path 44 b; asecond Fresnel lens 53 b is in component wavelength beam 54 b. In thegreen color channel, Fresnel lens 52 g is in illumination path 44 g; asecond Fresnel lens 53 g is in the modulated component wavelength beam54 g. In the red color channel, Fresnel lens 52 r is in illuminationpath 44 r; a second Fresnel lens 53 r is in modulated componentwavelength beam 54 r. With the arrangement of FIG. 10, first Fresnellens 52 r, 52 g, and 52 b in the illumination beam for each componentwavelength modulating section 114 r, 114 g, 114 b reduces the angle oflight directed into modulator panel 60, providing a measure ofcollimation, thereby improving the contrast performance. The secondFresnel lens 53 r, 53 g, and 53 b would be placed in modulated componentwavelength beam 54 r, 54 g, 54 b from LC modulator panel 60, to directthe light toward the entrance pupils of corresponding projection lenses62 r, 62 g, and 62 b.

In an alternate embodiment, a pair of crossed cylindrical Fresnel lensescan be used in one or more of component wavelength modulating sections114 r, 114 g, 114 b as an alternative to the conventional circularlysymmetric Fresnel lens types. Crossed cylindrical Fresnel lenses arerotated with respect to each other and can be further rotated at anangle to LC modulator panel 60 to minimize or eliminate moire andaliasing.

In one embodiment, projection apparatus 50 uses anti-ghost Fresnels,such as those produced by manufacturers such as Reflexite Corporation,Rochester, N.Y. As another alternative, holographic optical componentscould be used in the place of one or more of Fresnel lenses 52 r, 52 g,and 52 b. Glass molded Fresnel lenses would help to minimize problemswith stress birefringence from light absorption, such as decreasedcontrast uniformity across the image.

Control Loop for Projection Lens 62 r, 62 g, 62 b Alignment

FIG. 7 shows a control loop 100 arranged for automated alignment ofprojection lenses 62 r, 62 g, and 62 b. A sensor 104, such as anelectronic camera, senses light from a target 106 that may be part ofimage 64 on display surface 70 or may be separated from image 64. Target106 is devised to show proper overlap of the modulated component colorimages projected onto display surface 70. Methods such as thosedisclosed in commonly-assigned U.S. Pat. No. 6,793,351 (Nelson et al.)may be used to detect proper overlap at a control logic processor 108and to counter any offset between colors detected by sensor 104.Adjustment of projection lenses 62 r, 62 g, and 62 b may be effectedusing a combination of methods. Alignment in units of complete pixelscan be accomplished electronically, by shifting the position of thecorresponding red, green, or blue component modulating sections 80 r, 80g, and 80 b, using a method similar to that disclosed in U.S. Pat. No.5,729,245 (Gove et al.) Corresponding actuators 102 r, 102 g, and 102 b,such as stepping motors or piezoelectric actuators can be used to effectfine tuning alignment adjustment, either of full pixels or of fractionalincrements of a pixel, by moving projection lenses 62 r, 62 g, and 62 bthemselves. In one embodiment, a combination of the two methods is used,first attempting alignment by shifting the relative positions of one ormore of red, green, or blue component modulating sections 80 r, 80 g,and 80 b, utilizing pixels in border portions 82 r, 82 g, and 82 b asneeded. Following this shifting of red, green, or blue componentmodulating sections 80 r, 80 g, and 80 b, fine tuning adjustment is thenperformed by driving actuators 102 r, 102 g, and 102 b as needed.

ALTERNATE EMBODIMENTS

The embodiments shown in FIGS. 2, 4, 7, and 10 show projection apparatus50 using the conventional set of red, green, and blue component colors.Other arrangements are possible, including the use of additional colors,to provide an enhanced color gamut. Or, different component colors couldbe used to form color image 64. In an alternate embodiment using fourcolors, two LC modulator panels 60 could be used, each LC modulatorpanel 60 configured to have two component-color modulating sections.

In an alternate embodiment, a single LC modulator panel 60 is used incombination with a scrolling color filter device that separates thelight into color bands, separated by light blocking regions. The colorbands can be scanned across LC modulator panel 60 using prism optics orusing a color wheel or other type of color scrolling mechanism. Ablocking region is utilized to prevent color blurring during transitiontimes between the colors. The modulator is subsequently modulated insynchronization with the particular color light provided to apply theappropriate portion of the composite color image. Scrolling colorbackground and techniques are described, for example, in an articleentitled “Sequential Color Recapture and Dynamic Filtering: A Method ofScrolling Color” by D. Scott Dewald, Steven M. Penn, and Michael Davisin SID 01 Digest, pages 1–4.

In the alternate embodiment shown in FIG. 15, a projection apparatus 200uses a color scrolling element 140, such as a color scrolling wheel orsome combination of components including a color separator with ascanning prism, for example, that sequentially scans color light ofvarious wavelengths using techniques familiar to those skilled in thedigital projector arts. LC modulator panel 60 sequentially modulateseach incident color of light provided from color scrolling element 140to provide modulated light to a projection lens 62.

Another alternate embodiment of projection apparatus 200, as shown inFIG. 11, utilizes two modulator panels 60 c and 60 d, each with a colorscrolling element 140 c and 140 d, respectively. Each modulator panel 60c, 60 d has supporting optical components in its correspondingillumination path 44 c, 44 d, similar to that described with referenceto FIG. 2, and provides modulated light as a component wavelength beam54 c, 54 d to a projection lens 62 c, 62 d. Illumination section 68 ofthese embodiments using color scrolling components could employ colorseparation, color scrolling and light-directing techniques similar tothose disclosed in U.S. Pat. No. 6,280,034 (Brennesholtz), for example.

Where color scrolling element 140 c, or 140 d is a color scrollingwheel, a sequence utilizing repeated complementary pairs of colors maybe particularly advantageous. In such an arrangement, color scrollingelement 140 c could be a filter wheel having a red, green, and bluefilter for forming its set of colors. Color scrolling element 140 dwould then be a filter wheel having complementary cyan, magenta, andyellow filter for forming its set of colors. The sequencing of thesefilter wheels would be timed so that the combined image formed from thetwo modulator panels 60 c, 60 d would be additive with respect to color,with the combined image appearing to be white during each part of thescrolling sequence. This would be the case, for example, whensimultaneously projecting each primary color (red, green, blue) pairedwith its corresponding complement color (cyan, magenta, yellow).Combining this approach with the advantages of enhanced brightness andimproved imaging performance provided by the present invention allows anexpanded color gamut over earlier designs.

In an alternate embodiment, instead of providing two separate modulatorpanels 60 c, 60 d, a single modulator panel 60 could be subdivided intotwo segments. This would provided an arrangement similar to that shownin FIG. 3, but with two segments instead of three as shown in thefigure. One segment would serve for modulator panel 60 c, the othersegment for modulator panel 60 d.

Another alternate embodiment entails combining images from the threecolor component wavelength modulating sections 114 r, 114 g, and 114 bat an intermediate image plane. Referring to FIG. 12, there is shownprojection apparatus 50 wherein each component wavelength modulatingsection 114 r, 114 g, and 114 b provides a component of the modulatedimage to form image 64 as an intermediate image 146 for projection by aprojection lens 62. Lenses 63 r, 63 g, and 63 b direct modulated lightto form intermediate image 146. With this arrangement, intermediateimage 146 may actually be smaller than modulator panel 60, so thatintermediate image 146 can be magnified to the large screen size by asingle projection lens. Optical convergence can be done at the time offabrication, so that only a single projection lens adjustment isnecessary for an operator. This approach has been shown to be of valueas demonstrated in commonly-assigned U.S. Pat. No. 6,808,269 (Cobb) andU.S. Pat. No. 6,676,260 (Cobb et al.)

Referring to FIG. 8, there is shown a block diagram of projectionapparatus 50 in an alternate embodiment using individual red, green, andblue light sources 46 r, 46 g, and 46 b. Light sources 46 r, 46 g, and46 b may include lasers, LEDs, or other light source types and may alsobe supported by light conditioning components such as uniformizers, aswere described with reference to FIG. 2. Light sources 46 r, 46 g, and46 g may be polarized or provided with polarizers.

One advantage of the present invention is that compensators may not beneeded or at least that the need for compensators may be minimized. Asis well known in the art, there are two basic types of compensatorfilms. An uniaxial film with its optic axis parallel to the plane of thefilm is called an A-plate. An uniaxial film with its optic axisperpendicular to the plane of the film is called a C-plate. Alternately,the A-plate can be described as providing XY birefringence (ananisotropic medium with XY retardance) in the plane of the compensator,while the C-plate provides Z birefringence along the optical axis in thedirection of beam propagation through the compensator. A uniaxialmaterial with n_(e) greater than n_(o) is called positivelybirefringent. Likewise, a uniaxial material with n_(e) smaller thann_(o) is called negatively birefringent. Both A-plates and C-plates canbe positive or negative depending on their n_(e) and n_(o) values. As iswell known in art, C-plates can be fabricated by the use of uniaxiallycompressed polymers or casting cellulose acetate, while A-plates can bemade by stretched polymer films such as polyvinyl alcohol orpolycarbonate.

The present invention minimizes or eliminates the need for C-platecompensators, since using the larger LC panels as modulator panel 60results in reduced angular sensitivity. Referring to FIG. 12, a dottedline 142 indicates a possible position for an optional A-platecompensator in red component wavelength beam 54 r. Other componentwavelength modulating sections 114 r, 114 g, and 114 b may also benefitfrom an A-plate compensator in a similar position. Alternately, acompensator could be disposed in the illumination path, such as prior toFresnel lens 52 r, 52 g, 52 b, for example. In other embodiments,A-plate compensation may be supplemented with some additional level ofC-plate compensation. In still other embodiments, a C-plate compensatorwould be sufficient. Any of a number of types of compensator can beused, including film based compensators, compensators formed from amultilayer thin film dielectric stack, and compensators using formedbirefringent structures, for example.

In an alternate embodiment, as shown in the block diagram of a portionof a projection apparatus in FIG. 13, shown in perspective for clarity,a polarization beamsplitter 148 r, 148 g, 148 b is provided as ananalyzer for each modulated component wavelength beam 54 r, 54 g, 54 bfrom modulator panel 60. Polarization beamsplitters 148 r, 148 g, 148 b,wire grid polarization beamsplitters in one embodiment, turn the opticalpath of each component wavelength beam 54 r, 54 g, 54 b. In theembodiment of FIG. 13, projection lenses 62 r, 62 g, and 62 b then forman image on display surface 70. In another alternate embodiment, anintermediate image could be formed, as was described above withreference to FIG. 12.

Referring to FIG. 16, there is shown a portion of a one color channelusing a reflective polarization beamsplitter 148 as an analyzer. In thisembodiment, an optional additional analyzer 154 can be used, along witha Fresnel lens 156.

Referring to FIG. 14, there is shown a schematic block diagram of analternate embodiment in which modulated light from each color channel isdirected by lens 63 r, 63 g, 63 b to a V-prism assembly 150. V-prismassembly 150 combines the modulated light onto a single optical path forforming intermediate image 146 at the pupil of projection lens 62.V-prism assembly 150 is one type of color combiner using dichroicsurfaces and working in combination with mirrors 152 to direct lighttoward projection lens 62. Commonly-assigned U.S. Pat. No. 6,676,260(Cobb et al.) describes V-prism use in projection apparatus.

Where polarization beamsplitters 148 r, 148 g, 148 b are wire gridpolarization beamsplitters, such as those provided by Moxtek, Inc.,rotation of one of these devices about the optical axis can be used toprovide a measure of compensation, using methods disclosed incommonly-assigned U.S. Pat. No. 6,805,445 (Silverstein et al.)

By comparison with the conventional projection apparatus 10 in FIG. 1,the arrangement of projection apparatus 50 in FIGS. 2, 4, 8 and 12, andprojection apparatus 200 in FIG. 11 when adapted as described above,provides a system capable of considerably higher brightness levels.Where spatial light modulators 30 r, 30 g, and 30 b of the conventionalarrangement in FIG. 1 are miniaturized LCOS LC devices, the LaGrangeinvariant and energy-carrying capacity of these devices constrains theamount of brightness that is available to a range from about 5,000 to nomore than about 25,000 lumens. In contrast, the embodiment of FIGS. 2and 4 enjoys an expanded luminance range, allowing projection in excessof 30,000 lumens.

The dimensions of LC modulator panel 60 can be optimized to suit theperformance requirements of projection apparatus 50. In contrast to theminiaturized LCOS LCD solutions previously used, LC modulator panel 60can be a large scale device larger than typical laptop displays, up to17–20 diagonal inches or more. Although early LC panels weredisappointingly slow, ongoing work has provided speed improvements of100% and better and it appears that increased speeds are feasible.Improved response times of 8 msec or shorter have been reported.Ideally, modulator panel 60 can be sized just big enough such that thefull lamp system efficiency can be utilized and small enough to give thefastest response time, with the optimum size for pixel structure andelectronics to be fabricated utilizing standard TFT panel methods.

Sizing a TFT panel to be best suited to the lamp system efficiencyinvolves a number of considerations. For example, to utilize a Cermaxstyle lamp with a 2.0 mm arc gap, measurements show that the fullefficiency of the lamp can be captured by a system having a LaGrangeinvariant, defined as the product of the numerical aperture times thediagonal of the modulator area, of approximately 10. A system designedat f/10.0 has numerical aperture (NA) equal to 0.05. Thus, the devicediagonal would need to be 200 mm. This value would need to be doubled inorder to capture both polarization states. Additionally this modulationarea would be required for each wavelength band chosen. Thus, from asystem efficiency standpoint, a panel that is slightly larger than1074×358 mm would be very efficient and offer the best potential forfast transition times. The main difficulty would be to fabricate pixelelectronics to be small enough to accommodate this size at the highresolutions desired: 2048×1024 or 4096×2048 for each wavelength bandmodulated.

With its capability for using brighter light sources and use of alarge-area image generator, projection apparatus 50 using TFT LCmodulator panel 60 as in FIGS. 2 and 5 offers an overall efficiency onthe order of 40–50%. This is in contrast to the typical efficiency ofearlier LCOS LCD designs of FIG. 1, where efficiencies of no more thanabout 5 to 10% are common. Wire grid polarizers are particularlyadvantageous, since they exhibit relatively low light absorption. Ingeneral, a polarizer having light absorption of less than about 20%would be preferred. There may also be improved performance obtained byorienting the wire grid surface itself toward modulator panel 60 in theembodiments described above.

The invention has been described in detail with particular reference tocertain preferred embodiments thereof, but it will be understood thatvariations and modifications can be effected within the scope of theinvention as described above, and as noted in the appended claims, by aperson of ordinary skill in the art without departing from the scope ofthe invention. For example, the embodiments described hereinabove can beused to form an intermediate image, as was described with reference toFIG. 12, or to provide color modulated beams that are separatelyprojected onto display surface 70. Alternative types of more recentlyintroduced TFT components are possible, including organic thin-filmtransistors (OTFTs) based on conjugated polymers, oligomers, or othermolecules and thin film transistors utilizing monolayers ofwell-dispersed single wall carbon nanotubes.

Thus, what is provided is an apparatus and method for an electronicprojection apparatus using a TFT LC panel for forming the projectionimage.

PARTS LIST

-   10 projection apparatus-   20 light source-   20 r light source, red-   20 g light source, green-   20 b light source, blue-   22 uniformizing optics-   22 r uniformizing optics, red-   22 g uniformizing optics, green-   22 b uniformizing optics, blue-   24 r polarizing beamsplitter, red-   24 g polarizing beamsplitter, green-   24 b polarizing beamsplitter, blue-   26 dichroic combiner-   30 r spatial light modulator, red-   30 g spatial light modulator, green-   30 b spatial light modulator, blue-   32 projection lens-   34 lens-   38 lens-   40 display surface-   42 r condensing lens, red-   42 g condensing lens, green-   42 b condensing lens, blue-   44 illumination path-   44 c illumination path-   44 d illumination path-   44 d illumination path, red-   44 g illumination path, green-   44 b illumination path, blue-   46 r light source, red-   46 g light source, green-   46 b light source, blue-   48 r polarizer-   48 g polarizer-   48 b polarizer-   50 projection apparatus-   52 r Fresnel lens-   52 g Fresnel lens-   52 b Fresnel lens-   53 r Fresnel lens, red-   53 g Fresnel lens, green-   53 b Fresnel lens, blue-   54 c component wavelength beam-   54 d component wavelength beam-   54 r component wavelength beam, red-   54 g component wavelength beam, green-   54 b component wavelength beam, blue-   56 r analyzer-   56 g analyzer-   56 b analyzer-   60 modulator panel-   60 c modulator panel-   60 d modulator panel-   62 projection lens-   62 c projection lens-   62 d projection lens-   62 r projection lens, red-   62 g projection lens, green-   62 b projection lens, blue-   63 r lens, red-   63 g lens, green-   63 b lens, blue-   64 image-   66 polarized illumination beam-   68 illumination section-   70 display surface-   74 polarizer-   76 uniformized polarized beam-   78 color separator-   80 r red component modulating section-   80 g green component modulating section-   80 b blue component modulating section-   82 r border portion, red-   82 g border portion, blue-   82 b border portion, green-   84 a light blocking segment-   84 b light blocking segment-   90 a dichroic surface-   90 b dichroic surface-   92 turning mirror-   94 half wave plate-   96 polarizer-   98 mirror-   100 control loop-   100 r actuator, red-   100 g actuator, green-   100 b actuator, blue-   104 sensor-   106 target-   108 control logic processor-   110 polarized light providing apparatus-   114 r component wavelength modulating section, red-   114 g component wavelength modulating section, green-   114 b component wavelength modulating section, blue-   116 shutter-   118 LC modulator panel-   120 LC material-   122 thin-film transistor (TFT)-   124 ITO layer-   126 glass-   128 polarizer-   130 compensation film-   132 color filter array-   134 antireflection coating-   136 antireflection coating-   140 color scrolling element-   140 c color scrolling element-   140 d color scrolling element-   142 line-   146 intermediate image-   148 polarization beamsplitter-   148 r polarization beamsplitter, red-   148 g polarization beamsplitter, green-   148 b polarization beamsplitter, blue-   150 V-prism assembly-   152 mirror-   154 analyzer-   156 Fresnel lens-   200 projection apparatus

1. A projection apparatus comprising: a) an illumination sectioncomprising: i) a light source providing a substantially unpolarizedillumination beam of multiple wavelengths; ii) a multiple wavelengthpolarizer for polarizing the substantially unpolarized illumination beamto provide a substantially polarized illumination beam of multiplewavelengths; iii) a uniformizer for conditioning the substantiallypolarized illumination beam of multiple wavelengths to provide auniformized polarized beam of multiple wavelengths; iv) a colorseparator for separating the uniformized polarized beam of multiplewavelengths into at least a first component wavelength illumination anda second component wavelength illumination; b) at least two componentwavelength modulating sections, each component wavelength modulatingsection accepting a corresponding component wavelength illumination andmodulating the component wavelength illumination to provide a modulatedcomponent wavelength beam, each component wavelength modulating sectioncomprising: i) a portion of a monochrome transmissive liquid crystalmodulator panel that has been segmented into at least a first portionand a second portion, and wherein each portion is spatially separatedfrom each other portion; ii) a component wavelength polarizer in thepath of the component wavelength illumination for directingsubstantially polarized light to the corresponding portion of themonochrome transmissive liquid crystal modulator panel; iii) anillumination path Fresnel lens for focusing incident illumination fromthe component wavelength polarizer through the corresponding portion ofthe monochrome transmissive liquid crystal modulator panel; iv) ananalyzer for conditioning the polarization of the modulated componentwavelength beam; v) a lens for forming an image for projection onto adisplay surface; and whereby the image formed on the display surfacecomprises a plurality of superimposed component wavelength beams.
 2. Aprojection apparatus according to claim 1 wherein the light source istaken from the group consisting of an LED, an LED array, a Xenon lamp,and a Mercury lamp.
 3. A projection apparatus according to claim 1wherein the uniformizer comprises a lenslet array.
 4. A projectionapparatus according to claim 1 wherein the uniformizer comprises anintegrating bar.
 5. A projection apparatus according to claim 1 whereinthe transmissive liquid crystal modulator comprises thin filmtransistors.
 6. A projection apparatus according to claim 5 wherein thethin film transistors are organic thin film transistors.
 7. A projectionapparatus according to claim 5 wherein the thin film transistorscomprise carbon nanotubes.
 8. A projection apparatus according to claim1 wherein at least one component wavelength polarizer is spaced apartfrom the monochrome transmissive liquid crystal modulator panel.
 9. Aprojection apparatus according to claim 1 wherein the multiplewavelength polarizer is a wire grid polarizer.
 10. A projectionapparatus according to claim 9 wherein the wire surface side of the wiregrid polarizer device is oriented toward the liquid crystal modulatorpanel.
 11. A projection apparatus according to claim 1 wherein at leastone analyzer is a wire grid polarizer device.
 12. A projection apparatusaccording to claim 11 wherein the wire surface side of the wire gridpolarizer device is oriented toward the liquid crystal modulator panel.13. A projection apparatus according to claim 1 wherein at least onecomponent wavelength polarizer is a wire grid polarizer device.
 14. Aprojection apparatus according to claim 13 wherein the wire surface sideof the wire grid polarizer device is oriented toward the liquid crystalmodulator panel.
 15. A projection apparatus according to claim 1 whereinat least one illumination path Fresnel lens is spaced apart from themonochrome transmissive liquid crystal modulator panel.
 16. A projectionapparatus according to claim 1 further comprising: a) a sensor fordetecting an offset between the plurality of superimposed componentwavelength beams; and b) an imaging control processor for shifting theposition of at least one of the first or second portions on themonochrome transmissive liquid crystal modulator to compensate for theoffset.
 17. A projection apparatus according to claim 1 furthercomprising: a) a sensor for detecting an offset between the plurality ofsuperimposed component wavelength beams; and b) an actuator coupled withat least one projection lens for adjusting lens position to compensatefor the offset.
 18. A projection apparatus according to claim 1 whereinat least one of the component wavelength modulating sections furthercomprises a modulated beam Fresnel lens.
 19. A projection apparatusaccording to claim 18 wherein the modulated beam Fresnel lens is glass.20. A projection apparatus according to claim 18 wherein the modulatedbeam Fresnel lens comprises crossed cylindrical Fresnel lenses.
 21. Aprojection apparatus according to claim 1 wherein at least one of thecomponent wavelength modulating sections further comprises a modulatedbeam Fresnel lens, wherein the modulated beam Fresnel lens comprisescrossed cylindrical Fresnel lenses.
 22. A projection apparatus accordingto claim 1 wherein at least one of the modulated beam Fresnel lenses isglass.
 23. A projection apparatus according to claim 1 wherein theanalyzer in at least one component wavelength modulating sectioncomprises a wire grid polarization beamsplitter.
 24. A projectionapparatus according to claim 1 wherein the illumination section furthercomprises a shutter.
 25. A projection apparatus according to claim 1further comprising a compensator.
 26. A projection apparatus accordingto claim 25 wherein the compensator is placed between the modulatorpanel and the at least one component wavelength polarizer.
 27. Aprojection apparatus according to claim 25 wherein the compensator is afilm-based component.
 28. A projection apparatus according to claim 25wherein the compensator is a multi-dielectric thin film stack basedcomponent.
 29. A projection apparatus according to claim 25 wherein thecompensator is in the path of the first component wavelengthillumination.
 30. A projection apparatus according to claim 25 whereinthe compensator is in the path of a modulated component wavelength beam.31. A projection apparatus according to claim 1 wherein the analyzer isspaced apart from the liquid crystal modulator panel.
 32. A projectionapparatus according to claim 1 wherein at least one analyzer is areflective polarizing beamsplitter.
 33. A projection apparatus accordingto claim 1 wherein the illumination path Fresnel lens is glass.
 34. Aprojection apparatus according to claim 25 wherein the compensatorcomprises a formed birefringent structure.
 35. A projection apparatusaccording to claim 1 wherein the first and second component wavelengthillumination are selected from the group consisting of red, green, andblue illumination.
 36. A projection apparatus according to claim 1wherein the at least two component wavelength modulating sections forman intermediate image for projection by a projection lens.
 37. Aprojection apparatus according to claim 1 wherein the monochrometransmissive liquid crystal modulator panel has a first antireflectioncoating on a first surface and a second antireflection coating on asecond surface.
 38. A projection apparatus according to claim 36 furthercomprising a color combiner to combine modulated component wavelengthbeams for projection.
 39. A projection apparatus comprising: a) anillumination section comprising: i) a light source providing asubstantially unpolarized illumination beam of multiple wavelengths; ii)a multiple wavelength polarizer for polarizing the substantiallyunpolarized illumination beam to provide a substantially polarizedillumination beam of multiple wavelengths; iii) a uniformizer forconditioning the substantially polarized illumination beam of multiplewavelengths to provide a uniformized polarized beam of multiplewavelengths; iv) a color separator for separating the uniformizedpolarized beam of multiple wavelengths into at least a first componentwavelength illumination and a second component wavelength illumination;b) at least two component wavelength modulating sections, each componentwavelength modulating section accepting a corresponding componentwavelength illumination and modulating the component wavelengthillumination to provide a modulated component wavelength beam, eachcomponent wavelength modulating section comprising: i) a monochrometransmissive liquid crystal modulator panel; ii) a component wavelengthpolarizer in the path of the component wavelength illumination fordirecting substantially polarized light to the corresponding portion ofthe monochrome transmissive liquid crystal modulator; iii) anillumination path Fresnel lens for focusing incident illumination fromthe component wavelength polarizer through the monochrome transmissiveliquid crystal modulator; iv) an analyzer for conditioning thepolarization of the modulated component wavelength beam; v) a lens forforming an image for projection onto a display surface; and whereby theimage formed on the display surface comprises a plurality ofsuperimposed component wavelength beams.
 40. A projection apparatuscomprising: a) an illumination section comprising: i) a light sourceproviding a substantially unpolarized illumination beam of multiplewavelengths; ii) a multiple wavelength polarizer for polarizing thesubstantially unpolarized illumination beam to provide a substantiallypolarized illumination beam of multiple wavelengths; iii) a uniformizerfor conditioning the substantially polarized illumination beam ofmultiple wavelengths to provide a uniformized polarized beam of multiplewavelengths; iv) a color separator for separating the uniformizedpolarized beam of multiple wavelengths into at least a first componentwavelength illumination and a second component wavelength illumination;b) a first component wavelength modulating section, for accepting saidfirst component wavelength illumination and modulating said firstcomponent wavelength illumination to provide a first modulated componentwavelength beam comprising: i) a first monochrome transmissive liquidcrystal modulator; ii) a first component wavelength polarizer in thepath of the first component wavelength illumination for directingsubstantially polarized light to the first monochrome transmissiveliquid crystal modulator; iii) a first illumination path Fresnel lensfor focusing incident illumination from the first component wavelengthpolarizer through the first monochrome transmissive liquid crystalmodulator; iv) a first analyzer for conditioning the polarization of thefirst modulated component wavelength beam; v) a first lens for forming afirst image for projection onto a display surface; c) a second componentwavelength modulating section for accepting said second componentwavelength illumination and modulating said second component wavelengthillumination to provide a second modulated component wavelength beam,comprising: i) a second monochrome transmissive liquid crystalmodulator; ii) a second component wavelength polarizer in the path ofthe second component wavelength illumination for directing substantiallypolarized light to the second monochrome transmissive liquid crystalmodulator; iii) a second illumination path Fresnel lens for focusingincident illumination from the second component wavelength polarizerthrough the transmissive liquid crystal modulator; iv) a second analyzerfor conditioning the polarization of the second modulated componentwavelength beam; v) a second lens for forming a second image forprojection onto said display surface; and whereby the image formed onthe display surface comprises a plurality of superimposed componentwavelength beams.